T. B. KOSSETER ON LRBPANIDOTAENIA UNDULATA (KRABBE). 271 



U.S.A., in Journ. of Comp. Med. and Surg., vol. viii., January 

 1887, fell into the same error, no doubt misled by Dujardin's 

 work, and also at that time being unacquainted with Krabbe's 

 monograph. Leidy's own description shows that the tapeworm 

 he had under observation was not as he diagnosed it, T. angidata, 

 Rudolphi, but T. undulata, Rudolphi. 



The hooks of my own specimens of Drepanidotaenio undulata 

 correspond in detail with those of Krabbe's T. undulata. 



As will be seen above, the description of the internal anatomy 

 of this worm is very meagre, and under these circumstances 

 I purpose to fill up the void by describing more fully the organs 

 of generation. 



The testes (Figs. 3 and 4, d), from thirty to forty in number, are 

 situated dorsally in the posterior half of the proglottis. They 

 are more numerous in the proximal and distal portion of the 

 segment, but do not extend in either case beyond the lateral 

 canals. In the medio-posterior line they are very sparse. Each 

 testis sends off an efferent duct. These ducts coalesce until they 

 are reduced to three, and these are again further reduced to a 

 single duct, which becomes the vas-deferens, and, as such, enters 

 what in other instances would be a vesicula seminalis, but which in 

 this case is but an elongated cirrus-pouch. Consequently, there 

 is no actual vesicula seminalis, but the spermatozoa are passed 

 directly through the terminal duct to the cirrus within its pouch. 



The male genital pore (Fig. 4, a) is situated in the proximal 

 anterior third, on the dorso-lateral border of the segment, and is 

 posterior to the female pore. The male genital pore in its early 

 stage is but an insignificant aperture, and only when copulation 

 is about to take place does it become protuberant, and then not 

 to any great extent. 



The cirrus (Fig. 4, b) is a long rod, and is capable, for 

 copulatory purposes, of extending itself to a distance of 0*219 mm. 

 beyond the male genital pore. The cirrus itself is smooth, but 

 its cuticular sheath is spinous. This sheath is but a continuation 

 of the vas-deferens, and in the act of copulation it enters 



